What is the best definition for the word puerile?

The term "puerile" is defined as being characteristic of a child or being overly childlike in a way that is often considered immature or silly. This definition emphasizes the simplicity and naivety often associated with behavior that lacks the sophistication or responsible characteristics expected in adults. While "youthful" could suggest a connection to young people, it lacks the specific connotation of immaturity that "puerile" carries. Likewise, "sophisticated" and "virtuous" are terms that describe qualities of maturity and morality, which contrast with the essence of being childish and naive, highlighting the lack of seriousness in behavior described by "puerile." Therefore, the most accurate definition aligns closely with childishness.